Sheet stack leveler for printing press



June 30, 1970 F. H. PAQUE 3,517,824

SHEET STACK LEVELER FOR rniunne PRESS Filed April 50, 1968 I! I afze MM MM, #0044. flftarzqgs' United. States. Patent 3,517,824 SHEET STACK LEVELER FOR PRINTING PRESS Francis H. Paque, 538 N. 51st St.,

Milwaukee, Wis. 53208 Filed Apr. 30, 1968, Ser. No. 725,391 Int. Cl. A47f 7/00 US. Cl. 211-50 6 Claims ABSTRACT OF THE DISCLOSURE Disclosed herein is a sheet stack leveler for use with a printing press to prop up the thin side of sheets in a stack of sheets of non-uniform thickness, thus to maintain the sheets in a horizontal rather than slanted plane and facilitate operation of a printing press sheet feed mechanism. The leveler comprises a base having an upstanding post with a series of vertically spaced swingably mounted prop blades. Only as many prop blades as are necessary are swung into the stack of sheets in successively spaced vertical intervals to obtain the desired leveling.

BACKGROUND OF INVENTION The sheet pick-up devices on the feed mechanism of printing presses, such as the type of feeding mechanism employing suction feet, do not operate effectively with sheets which are at a slant with respect to the horizontal. When envelopes or stapled sheets or other materials of non-uniform thickness are in a stack, the extra thickness caused by the staples or envelope flaps causes the top sheet to be at a slant.

SUMMARY OF INVENTION The invention provides a sheet stack leveler which comprises a base having an upstanding post which rotatably or swingably supports a series of thin, vertically spaced prop blades. The leveling of a stack of sheets of non-uniform thickness is quickly achieved by swinging a sufficient number of prop blades into intervening relationship between the thin sides of the sheets.

The vertical spacing of the prop blades can readily be varied by adding or subtracting the number of prop blades which are inserted into the stack. To vary the extent of projection of prop blades from the post into'the stack of sheet materials, the prop blades are provided with a series of longitudinally aligned apertures for receiving the upstanding post.

The base is movable relative to the prop blades, thus the base can be located at an appropriate clamping or anchored position on a support which is typically part of a vertical feed mechanism on the printing press.

Further objects and advantages of the invention will become apparent from the following disclosure.

DRAWINGS FIG. 1 is a perspective view of a sheet stack leveler embodying the invention.

FIG. 2 is a fragmentary vertical sectional view of the device shown in FIG. 1.

FIG. 3 is a fragmentary perspective view showing the sheet stack leveler shown in FIG. 1 in use with a printing press.

DETAILED DESCRIPTION Although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention which may be embodied in other Specific structure. The scope of the invention is defined in the claims appended hereto.

3,517,824 Patented June 30, 1970 In the drawings, FIG. 1 discloses a sheet stack leveler which is generally designated 10 and which is utilized with a prniting press to level the thin sides of sheets in a stack of materials of non-uniform thickness to facilitate operation of the printing press feed mechanism. The stack leveler includes a base 12 which has a threaded aperture 14 (FIG. 2) for threadably receiving an upstanding post 16. The base is desirably in theform of an elongated narrow flat plate or blade which is perpendicular to the post 16.

The sheet stack leveler 10 also includes a series of vertically spaced relatively thin prop blades 18 which are separated by relatively thicker spacers or guides 20 and which are swingably mounted on the post 16. Each prop blade 18 has corresponding spaced apertures 19, 21, 22 for alternatively receiving the post 16. The extent of projection of a prop blade 18 into a stack of sheets can be varied by choosing the appropriate aperture 19, 21, 22. When using the sheet stack leveler 10 with a stack of small envelopes or other small sheets, the prop baldes do not have to project into the stack to the same extent as with larger sheets, such as are bound into booklets, to accomplish the desired leveling.

The prop blades 18 are sandwiched between the spacers 20 and secured in a stacked vertical array by a cap nut 24 which is threadably received on the upper end 26 of the post 16. The degree of clamping engagement of spacers 20 on the prop blades 18 can be varied by adjusting the tension of the nut 24 against the upper pro-p blade 18.

When the sheet stack leveler 10 is in use, as shown in FIG. 3, the base 12 can be secured to a support bed 28 by any convenient means such as C-clamp 30. The support 28 will typically be a bed portion of a vertical feed mechanism which sequentially raises during the printing operation to raise the stack of sheets within the range of the sheet pick-up mechanism 3'6 of the printing press 38. Pick-up mechanism 36 typically has suction feet along the length. It swings on arms 39 in the direction of the arrows to successively feed the top sheet or booklet from the stack 44 into the press 38. The thick margins 45 of the sheets or booklets in the stack 44 are adjacent the press 38. The thin margins 46 are remote from the press and are adjacent the leveler 10.

The prop blades 18 are individually swung into intervening relation with the stack of sheets at vertically spaced intervals 40 to level the thin margins of the stack 44 of sheets. The sheets can then be picked up by the feed mechanism 36 of the printing press 38.

I claim:

1. For use in a feeder for a printing press, a sheet stack leveler for leveling the thin side of a stack of sheets of non-uniform thickness, said sheet stack leveler comprising a base, an upstanding post connected to said base, a plurality of relatively thin prop blades, relatively thick spacers between said prop blades, means for swingably mounting said prop blades to said post to intervene in the thin side of said stack at successively spaced vertical intervals to level the thin side of the sheets within the intervals.

2. A sheet stack leveler comprising a base, an upstanding post connected to said base, a plurality of prop blades, means for swingably mounting said prop blades to said post to intervene in the thin side of a stack of sheets having a non-uniform thickness, at successively spaced vertical intervals to level the thin side of the sheets within the intervals, each of said prop blades having a series of spaced apertures for selectively receiving said post to vary the extent of projection of said blades from said post into a stack of sheet material.

3. A sheet stack leveler in accordance with claim 1 wherein said spacers are removably received by said post.

4. The sheet stack leveler of claim 1 including a cap nut wherein the upper end of said post is threaded to receive said nut, said nut and said thread on said post cooperating to afford variation of clamping pressure on said prop blades.

5. A sheet stack leveler in accordance with claim 1 wlherein said prop blades are in spaced relation and stacked array for selective movement about a common axis between positions of non-intervening relation to positions of intervening relations with a stack of sheet materials.

6. The invention of claim 1 in which said base comprises a narrow flat blade also swingably mounted on said means.

References Cited UNITED STATES PATENTS 2,443,696 6/ 1948 Siteman 211-40 2,692,689 10/ 1954 Wynne 211-165 JAMES A. LEPPINK, Primary Examiner US. Cl. X.R. 21 1-165 

